What Are the Stages of Breast Cancer?

(information courtesy of breastcancer.org)

Stage 0

Describes cancer that is non-invasive. In other words, the cancer is still in the area in which it started and has not invaded nearby tissue. (Lobular carcinoma in situ and ductal carcinoma in situ for example.)

Stage I

The tumor is less than 2 centimeters (cm) and there are no lymph nodes involved although the cancer cells are invading neighboring normal tissue in the breast.

Stage II

The tumor is between 2 and 5 cm and/or has spread to the lymph nodes under the arm on the same side as the cancer. The lymph nodes are not yet sticking to one another or the surrounding tissues.

Stage III

(which has 2 sub-stages):

Stage IIIAThe tumor measures 5 cm and/or the surrounding lymph nodes are sticking to one another and the surrounding tissue.

Stage IIIBThe tumor is any size and has spread to the breast skin, chest wall, or internal mammary lymph nodes.